1. Field of Invention
The invention relates to an extraction device and, in particular, to a solid-phase micro extraction device.
2. Related Art
When analyzing organic components of a complex sample, one often uses such techniques as liquid-liquid extraction, solid-phase extraction (SPE), and super-phase extraction (SFE). However, these methods have different kinds of defects, such as high costs, complicated operations, long operation time, or pollution of organic solvents poisonous to human bodies. The traditional solid-phase micro extraction (SPME) developed according to the SPE has the advantages of a shorter sample processing time in the sample pretreatment, simpler operation steps, reduced organic solvent uses, and reduced loss of analyzed materials.
This invention develops a novel solid-phase nano extraction (SPNE) device that overcomes defects in conventional sample pretreatment technology. It does not need any solvent and complicated devices. It can directly extract volatile and nonvolatile compounds from aqueous and gaseous samples. The sampling in this method uses a SPNE fiber assembly, which consists of a holder and a fiber. FIG. 1 shows a conventional SPNE fiber assembly. The holder 10 includes a handheld bar 11, a push rod 12, and an adjustable depth gauge 13. The rear end of the handheld bar 11 is connected to the push rod 12 to control the action of a Z-shaped connection rod 14 inside the handheld bar 11. The front end of the handheld bar 11 is connected to the depth gauge 13. The front end of the depth gauge 13 is connected to the fiber 20. The fiber 20 contains a probe 21 whose front tip is a fused-silica rod probe 21 with a diameter of about 0.5 mm, and it is surrounded by a hollow stainless tube 22. The surface of the fused-silica rod used for extraction is coated with a compound layer of PDMS and adsorbing materials. Through the driving of the Z-shaped connection rod 14 connected to the push rod 12, the probe 21 is controlled by the push rod 12 to push out or pull in. When sampling, the user pushes the push rod 12 so that the front fused-silica rod of the probe 21 is exposed in the sample. The probe retracts after finishing sampling. The SPNE fiber assembly is installed in an analyzing apparatus, such as a gas chromatography (GC) or a high performance liquid chromatography (HPLC). The probe extends into the analyzing apparatus for departure in order to complete subsequent analyses.